This is super cool: "Solid Fordite cabochon, known locally as Detroit Agate. Not an agate at all, though, merely a happy accident! The original material was created many years ago at the Ford Rouge Plant just outside of Detroit, Michigan.
" The diamond has a thousand facets, but the facets are covered with dirt and tar. It is the job of the soul to clean each facet until the surface is brilliant and can reflect a rainbow of colors. The diamond is perfect, not one flaw. The only differences
Gem quality sphalerite is a rare collector stone. The mineral is usually nearly black in color but is occasionally found in transparent pieces of an orange or yellowish brown hue. Clean pieces are extremely rare.